Adjustable high and low pressure control for radial pumps



W. ERNST Jan. 2s, 1941.

ADJUSTABLE HIGH MID LOW TRESSURE CONTROL FUR HBINL PUMPS 2 Shams-Sheet l JMW WALTER ERNST,

Filed `Jullg] 19, 193B E. mbwww 4...', Q D .3. @E

Jan. 2s, 1941'. l w. ER-NST 2,230,054

ADJUSTABLE HIGH AND LOW PRESSURE COTROL FOR RADIAL PUMPS Filed July 19. 1958 2 sheds-sheet 2 .Ewoud-rw, 'By WALTER ERNST,

SM fsm A @uvm Patented Jan. 28, 1941 UNITED STATES ADJUSTABLE HIGH AND LOW PRESSURE CONTROL FOR RADIAL PUIVIPS Walter Ernst, Mount Gilead, Ohio, assgnor to The Hydraulic Development Corp. Inc., Wilmington, Del., a corporation of Delaware Application July 19, 1938, Serial No. 220,046

7 Claims. (Cl. 103-38) This invention relates to hydraulic control systems, and in? particular, to pressure control systems for hydraulic radial pumps.

One object of this invention is toprovde a pressure fluid delivery control for high and low pressures in radial pumps, wherein means is provided for shifting the pressure control of the pump from one pressure fluid delivery level to another such level either automatically or at the will of the operator.

Another object is to provide such a control for radial pumps, wherein the pressure fiuid delverylevels are adjustable by minute increments.

Another object is to provide such a control for radial pumps, wherein the fluid flow-controlling member of the pump is arranged to be shifted to one position upon the attainment o-f a predetermined pressure in the delivery of the pump, and thereafter to another position representing another pressure fluid delivery level.

Another object is to provide such a control for radial pumps, wherein themeans for shifting the flow-control member or shift ring of the pump is operative in opposition to a servomotor for shifting the flow-control member in the opposite direction. v

Another object is to provide an adjustable high and low pressure control mechanism for radial pumps, wherein, the' intensity of the pressure delivered to the fluid by the pump may be supplied initially at one pressure stage or level and then shifted automatically or at the will of the operator, or after a predetermined time interval, to another stage or pressure level, the pressure difference between the two levels being adjustable by small increments.

Another object is to provide an adjustable high and low pressure control for radial pumps, Wherein the pump servomotor ,for shifting the now control member or shift ring of the pump is arranged in a plurality of stages having different piston areas, these being opposed by resilient means, such as a spring, so that different degrees of fiuid pressure supplied to different piston areas of the servomotor piston will shift the pump flow-control member to its neutral or no delivery position by overcoming the thrust of the resilient means or spring.

Another object is to provide such a pressure control for radial pumps as described in the paragraph immediately above, wherein ud pressure means is provided for shifting the flowoontrol member or shift ring of the pump in a direction opposite to the shifting direction of the servomotor piston, and preferably against a stop the position of which may be adjusted.

In the drawings: `Figure 1 is a transverse section through radial pump em'bodying the adjustable high and low pressure control of this invention.

Figure '2 is a diagrammatic View, partly in section, of a hydraulic press control circuit utilizing the adjustable high and low pressure controlled radial pump of this invention.

In general, the adjustable high and low pressure control for radial pumps of this invention consists of a means for adjustably shifting theV pressure control, such as the shift ring of the pump, to a plurality of different stages so that the pump may deliver pressure fluid up to a certain predetermined pressure and then shift to its neutral or no delivery position, after'which time it may again be placed upon delivery up to the attainment of a new-and different pressure level, whereupon it again shifts to its neutral or no delivery position.

Referring .to the drawings in detail, Figure 1 sho-ws a pump having a casing III with pads II having flat surfaces I2 for reciprocably supporting the shift ring or now-control member I3 of the pump, bearing plates I4 being inserted therebetween. Rotatable within the shift ring I3 of the pump is a secondary rotor I5, provided with lateral grooves I6 engaged by rollers I1 mounted upon shafts I8, passing through the heads I9 of pistons 2l). The latter are reciprocable in radial bores 2| in a primary rotor or cylinder barrel 22 around a fixed pintle 23. The latter is provided with cutaway portions 24 and 25 communicating, respectively, with longitudinal pairs of ports 26, 21, through which fluid is conveyed to and from the cylinder bores 22 by means of the ports 28. The details of construction of the pump mechanism Within the shift ring I3 form no part of the present invention, andmay consist of one or a variety of forms. A typical form of such a pump is disclosed in the cepending application of Walter Ernst, Ser. No. 87,028, led June 24, 1936, which` application matured into United States Patent No. 2,159,533, dated May 23, 1939.

The shift ring I3 is provided with diametrically disposed bosses 30, having threaded sockets 3| for the reception of the shift rods 32 and 33, respectively passing through bores 34 and 35 in the pump casing I0. The bores 34 and 35 are provided with leak-age chambers 36 having leakage passageways 31 leading back to the interior of the casing III. The pump casing III is provided with side portions 38 and 39, containing the bores 34A and 35 and having flattened end surfaces 40 and 4|, respectively. Clamped against the end surface 40, as by .the screws 42, is,the corre- 5 spend-ing surface 43 of the servomotor casing 44. The latter contains a cylinder bore, generally designated 45, and having three portions 46, 41 and 48. The cylinder bore 45 is closed by a cylinder head 49 secured by the screws 50 to the servomotor casing`44.

Reciprocable within the cylinder bore 45 is a stepped piston head, generally designated 5|. The latter is mounted upon the shift rod 32 and limited in its position thereon by the head 52 and the collar 53. Leakage escaping past the piston head 5| drains back into the interior of the casing I by way of the passageways 54 and 55 in the shift rod 32, and thence by way of the longitudinal passageway 56, through the piston head into the chamber 36 and passageway 31. The collar 53 is provided with a conical end 51 cooperating with a similar conical surface 58 in the piston head 5|. The latter is provided with portions of different diameters, with annular shoulders or piston areas 59 and 60 therebetween. The piston area 59 opens into a chamber 6| with a port 62 leading thereto, whereas the piston area 60 opens into a chamber 63 having a similar port 64 leading thereto. Longitudinal passageways 65 and 66 lead from the ports 62 and 64 to the end ports 61 and 68, respectively. The ports 61 and 68 are threaded so that they may be closed by means of threaded plugs. The provision of the piston areas 59 and 60 enables the exertion of different thrusts against the piston head-5| because of the difference in the areas of these annular piston surfaces.

Secured to the fiat surface 4| of the side portion 39, as by the screws 69, is the control casing 1 I. The control casing 1| is provided with a slot 1| within which a yoke 10 is arranged to slide. 'I'he control casing 1| is also provided with a cylindrical bore 12, having therein a sliding sleeve 13 for receiving a coil spring 14. One end of the 45 latter bears against the yoke 10 and the other end against the internal ange 15, having on its opposite side the collar 16 and ball thrust bearing 11 engaged by the hub 18 of a hand wheel 19. 'Ihe latter is provided with a threaded bore 80 engag- 0 mg the threaded end sl of the shift rod 33 and locked in any desired position by the loclmut 82.

A retaining nut 83 is mounted on the extreme end of the threaded end'8I. By rotating the hand.

wheel 19 the coil spring 14 may be caused to en- 55 gage the flange 15 of the sleeve 13 with varying pressure, which is transmitted, through the shift rod 33, to the pump shift ring I3, and opposed by one of the piston areas upon the servomotor piston head 5|. a 00 The control casing 1| is likewise provided with aJ pair of cylinder bores 84 having communicating ports 85 and 86 at opposite ends thereof. Reciprocable in the cylinder bores 84 are piston heads 81 with piston rods 88 threaded therein, as 55 at 89. 'I'he opposite ends of the piston rods 88 are threaded into the sockets 90 of the yoke 10.

Surrounding the piston rods 88 are the packings 9|, compressed by the glands 92 for the purpose of preventing leakage. The cylinder bores 84 are .70 closed at their opposite ends by the cylinder heads 93, having apertures 94 through which pass the stop rods 95, the opposite ends of which are i threaded as at 96 into the ring 91. The latter is provided with a ridge 98 engaging a corresponding 75 groove 99 in the hub |00 of a hand wheel |0|.

The hub I 00 is threaded internally, as at I 02, and engages the threaded portion |03 upon the outer surface of the control casing 1 I. When the hand wheel |0I is rotated the stop rods 95 are advanced into or withdrawn from the chambers within the cylinder bores 84, thereby providing adjustable abutments against which the piston heads 81 will come to rest when the pressure fluid is supplied thereto through the ports 86. Oil seals |04 prevent leakage around the stop rods 95 and are held in position by the retainers |05.

The radial pump and its associated control mechanism shown in Figure l may be utilized in a variety of circuits. One such circuit is shown in Figure 2, and consists of the pump, generally designated |06,`with its servomotor, generally designated |01, and control device, generally designated |08. 'I'he casing I0 of the pump |06 is provided with end plates |09, to one of which is secured the fluid outlet connection ||0 having a pressure connection ||I and a suction connection ||2. A suction pipe I|3 runs downwardly from the suction connection ||2, into the interior of a fluid tank ||4. Running from the pressure connection |I| is a pipe ||5 leading to a four-way valve, generally designated ||6, from which the lines I1 and I |8 lead respectively to the ports I9 and |20 at the opposite ends of the main cylinder |2| of a hydraulic press, generally designated |22 This press is represented diagrammatically, and contains a piston |23 with a piston rod |24, these being reciprocable within the cylinder bore |25 within the main cylinder |2I. The hydraulic press |22 is provided with a frame |26 connecting the main cylinder |2`| with the press bed |21, upon which the workpiece or die is supported. The piston rod |24 is provided with an arm |28, arranged to operate a limit switch, in a manner subsequently to be described.

The four-way valve ||6 is of a conventional type, and consists of a casing |30 having a bore I3 I, within which reciprocate the valve heads |32 and |33 on the valve rod |34. At the end of the latter is a handle |35, shown diagrammatically as a ball, but alternatively consisting of a lever or any other suitable means of shifting the valve rod |34. The casing |30 is provided with a central port |36 for theconnection of the pump pressure line ||5, and end ports |31 and |38 from which the exhaust line |39 runs to the tank ||4. Also provided are two intermediate ports |40 and |4|, from which the lines ||1 and ||8 lead respectively to the main cylinder ports I|9 and |20, as previously stated. By shifting the valve rod |34 and its heads |32 and |33, the ilow from the pump, through the pump pressure line ||5, may be directed either to the upper or lower part of the main cylinder |2I, while the opposite side thereof is connected to the exhaust line I 39, in the manner well known to those skilled in the art. Thus, the .shifting of the four-way valve ||6 controls the distribution of pressure fluid from the pump to the press |22 in order to advance or retract the piston |23 and its piston rod |24.

The portion of the hydraulic circuit by which the pump and servomotor control systems are operated includes a three-way valve |42, of a conventional type, and having a valve rod |43, terminating in the armature |44 adapted to be shifted by the energization of the solenoid |45. The latter is connected to an electrical circuit, in a manner subsequently to be described. From the three-way Valve |42 the exhaust conduit |46 leads downwardly to the fluid tank ||4, whereas the acconti.

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right-hand ends of the cylinder bores 34 (Figure l), from the opposite ends of which the exhaust line |48 leads downwardly to the fluid tank II4. The three-way valve |42 is supplied by pressure :duid through the conduit |49 leading to it from the pump pressure fluid line I I5, a branch conduit |50 proceeding to one or both ofy the ports 62 or 0| in the servomotor casing 44 (Figure 2).

The servomotor |01 may be caused to become operative and shift the shift ring I3 of the pump i |0| to its neutral or no delivery position at any one of three predetermined pressures for the same setting of the thrust of the coil spring 14 (Figure l). rlhese three different pressures are determined by the area on the servomotor piston head 5|, which is subjected to a pressure fluid reaching it`from the conduit |50. If both of the an-y nular piston areas 59 and 60 in the chambers 0| and 63 are subjected to this pressure fluid, then the maximum area of the servomotor piston is in use, and a relatively low pressure in the conduit |50 will cause the servomotor piston 5| to shift and overcome the thrust of the coil spring in order to place the pump shift ring |3 in its neutral or no delivery position. If the annular piston area 50 alone is subjected to this pressure fluid, then an intermediate pressure will be required to overcome the thrust of the coil spring and place the pump lin its no delivery position. If, however, the smaller annular piston area is alone subjected to this pressure uid, then a relatively high pressure in the conduit |50 will be required to overcome the thrust of the coil spring '|0 and shift the pump shift ring I3 to its neutral orno delivery position. y

'll'o utilize both piston areas 59 and 60 the ports and 63 are unplugged while the port 62 remain plugged, thereby establishing a connection between the chambers 63 and 6| by Way of the longitudinal bores 66 and 65. If the larger annular piston area 59 is to be utilized, the conduit |50 is connected to the port 62, and the ports 5|, 03 and 64 are plugged. If, however,- the smaller piston area 60 is to be utilized, the ports 0|, 60 and 62 are plugged, in the manner shown in Figure l. v

The electrical circuit for energizing the solenoid |45 includes the lines |5| and |52, leading to the contactor |53 having normally open switch blades |54 and4 |55, adapted when closed `to connect the lines |5| and |52, respectively, with the power lines |56 and |51. The operating coil |50fof the contactor |53 is connected, by the lines |59 and |60, to the timing device |6| from which `the lines |62 and |63 lead, respectively, to the power line' |51 and to the normally 'open limit switch |64. The limit switch |64 is adapted to be closed by the press arm |20 Vwhen it reaches a predetermined position, thereby connecting the line |63, through the limit switch |64, to the line |65 leading tothe power line |56. 'Ihe spring |66 normally opens the limit switch |64 when the press arm |28Y is retracted.

Operation In the operation of the circuitshown in, Figure 2, let it be assumed that a relatively high pressure is desired to shift the pump shift ring I3 to its neutral position so that the connections is given the desired thrust so that, for example, a pressure of 500 pounds per square inch is required at the annular piston area. 60 to compress the coil spring 14 and move the pump shift ring I3 to its neutral or no delivery position. Let it .be assumed that the pump |06 is in operation,

delivery position. The pump |06 will therefore.

temporarily hold the pressure 'in the pressing cylinder |2| at 500 pounds per square inch. Meanwhile, at the time the press closed, its arm |20 closed the limit switch |6d, thereby starting the timing device |0 After the expiration of the time period for which the timing device |60 is set, the latter closes the circuit, energizing the operating coil |50 of the contactor |53, shifting its switch blades |50 and |55 into a position to energizethe solenoid |45. The latter then shifts the valve rod |43 of the three-way valve |42 so as to admit pressure from the conduit |49 to the conduit |41, and thence into the cylinder 'bores 84 A against the pistons 81.

The pistons 01 then move to the left (Figure l) carrying with them the yoke 10 and further compressing the coil spring 14. This action causes the shift rod' 33 to move to the left, under the increased thrust of the coil spring 14, carrying with vit the pump shift ring |3, shift rod 32 Vand servomotor piston head 5|. The pistons 81 come to rest against the ends of the stop rods 95, the positions of which may be adjusted by turning the hand wheel I0 thereby regulating the additional compression placed upon the coil spring 14, and hence, adjusting the high pressure stage of the pump. The pressure of 500 pounds per square inch now standing in the conduit |50 is therefore no longer sufficient to overcome the increased thrust of the coil spring 14. Accordingly, the pump Vagain delivers pressure uid to cause the piston |23 and its piston rod |24 to exert an increased pressing effect, until the pressure rises,` to a sufficient amount where it will again act no delivery position automatically and Without the necessity for attention on the part of the operator I l When the four-Way valve ||6 is shifted to supply pressure fluid to the port |20 and retract the pressing piston |23, the limit switch |64 is opened and deenergizes the timing device |6I, in turn deenergizing and opening the contactor I53.and consequently deenergizlng the solenoid I4 The three-way valve |42, therefore, shifts into a. position closing off the conduit |40 from communication with the conduit |41, and connecting the latter to the exhaust conduit |46 The pressure is thus released from the right-hand ends of the cylinder bores 84 (Fig. 1) so that the thrust of the coil ring 14 moves the yoke Il and piston heads 8l to the right to the positions shown in Figure 1. The electrical and hydraulic circuits are thus placed in readiness for the resumption of another pressing stroke, and the parts come to rest in the positions shown in Figure 2.

In the circuit shown in Figure 2 the pressure fluid employed in the hydraulic circuit has also been utilized for shifting the pistons 87. It will be obvious, however, 'that pressure fluid from any source, such as air pressure, may be used to shift these piston heads. It is also obvious that the timing device ISI may be omitted, and is also obvious that the three-way valve M2 may be shifted manually when the operator wishes to apply the additional pressing pressure. Alternatively, the three-way valve N2 may be shifted by some portion of the machine when it reaches a predetermined position, such as directly by the press arm |28.

The servomotor arrangement containing a plurality of annular piston areas adapted selectively to be subjected to pressure uid in the hydraulic circuit is disclosed and claimed in the copending application of Ernst, et al., Ser. No. 225,155, led August 16, 1938. It will be observed, however, that the servomotor would be operative for the present purpose with the employment of a single piston area instead of the more convenient pluraly piston arrangement shown in Figure l.

It will be understood that I desire to comprehend within my invention such modifications as come within the scope of the claims and the invention.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In a control deviceior a variable delivery pump with a shiftable flow-control element,r

pressure-fluid-respcnsive means for shifting said flow-control element in one direction, yielding means for urging said flow-control element in the opposite direction, movable means acting upon one side of said yielding means for adjusting the thrust of said yielding means, hydraulic means operable independently of said movable means and acting upon the opposite side of said yielding means for selectively applying increased thrust through said yielding means against said flow-control element and stop means adjustable relative to said movable means and said hydraulic means for limiting the motion of said hydraulic means.

2. In a control device for a variable delivery pump with a shiftable flow-control element, pressure-iluid-responsive means for shifting said dow-control element in one direction. yielding means for urging said dow-control element in the opposite direction, manually operable means adapted to act upon one side of said yielding means for adjusting the thrust of said yielding means, and hydraulic means operable independently of said manually operable adjusting means and adapted selectively to .apply increased thrust on the other side of said yielding means for actuating said iiow control element.

3. In combination with a variable delivery pump having a shiftable now-control element, Vpressure-fluid-responsive means arranged on one side of saidiiow-control element and adapted to shift the `latter in one direction, yielding means arranged only on the other side of said ow control 'element for urging said dow-control element in the opposite direction, mechanical 'pressure-iluid-responsive means for means adapted to act upon one side of said yielding means for adjusting the thrust of said yielding means, and hydraulic means independent of said mechanical thrust-adjusting means for selectively applying increased thrust on the other side'of said yielding means against said flow control element.

4. In combination with a variable delivery pump having a shiftable now-control element, pressure-fluid-responsive means arranged on one side of said flow-control element for shifting said flow-control element in one direction, yielding means arranged on the other side vof said owcontrol element only, for urging said flow-control element in the opposite direction, first adjusting means acting upon one sideL of said yielding means and operable to vary the thrust thereof, hydraulic means independent of said rst ad- J'usting means for selectively applying increased thrust on the other side of said yielding means against said flow control element, and stop means adjustable independently of and relative to said first adjusting means and said hydraulic means for limiting the motion of said hydraulic means.

5. In a control device for a variable delivery pump with a shiftable flow-control element, pressure-fluid-responsive means for shifting said dow-control element in one direction, yielding means for urging said flow-control element in the opposite direction, a first thrust-adjusting member adjustably engaging said yielding means,

a second thrust-adjusting member engaging said yielding means oppositely from said irst thrust-adjusting member, and a fluid pressure motor for selectively moving said second thrustadjusting member in a direction adapted to apply an increased thrust through said yielding means against said flow-control element.

6. In a control device for a variable delivery pump with a shiftable now-control element, pr'essure-iiuid-responsive means for shifting said now-control element in one direction, yielding means for urging said flow-control element in the opposite direction, a iirst thrust-adjusting member adjustably engaging said yielding means, a second thrust-adjusting member engaging Said yielding means oppositely from said first thrustadjusting member, a iiuid pressure motor for selectively moving said second thrust-adjusting member in a direction adapted to apply an increased thrust through said yielding means against said flow-control element, and means for limiting the motion of said second thrust-adjusting member.

7. In a control device for a variable delivery pump with a shiftable flow-control element, shifting said now-control element in one direction, yielding means for urging said flow-control element in the opposite direction, a first thrust-adjusting member adjustably engaging said yielding means, a second thrust-adjusting member engaging said yielding means oppositely from said irst thrustadjusting member, a fluid pressure motor for selectively moving said second thrust-adjusting member in a direction adapted to apply an increased thrust through said yielding means against said now-control element, and a movable stop device for adjustably limiting the motion of said second thrust-adjusting member.

' WALTER ERNST. 

